Introduction; Product Overview - ABB ATS021 Installation And Operating Instructions Manual

Automatic transfer switch

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Installation and operating instructions, ATS021

3. Introduction

The automatic transfer switch ATS021 is used in all installations where switching is required between two

lines to ensure the supply of loads in case of a fault on one line.

ATS021 selects the power supply line by acting directly on the CBs provided on the lines: ATS021 can be

used with automatic CBs and ABB SACE switch-disconnectors.

The device monitors the voltage of the main line and emergency line and records the following faults:

• Maximum and minimum voltage (up to +/-30%)*

• Maximum and minimum frequency (0.9fn>f>1.1fn)

• Phase balance

• Frequency imbalance**

• Voltage imbalance***

* Max. +20% in case of 480 VAC voltage and min. -20% in case of 208 VAC voltage

** In case of frequency imbalance, the fixed threshold +/- 10% is also applied to the difference between

the two frequency values of the phases.

*** In case of imbalance of voltage, the threshold set by means of the Lim selector is also applied to the

difference between the voltage values of the phases.

Depending on the settings and the anomalies recorded, the device pilots the CBs on the power supply

lines to ensure continuous power supply of the plant.

ATS021 does not require an auxiliary safety power supply since it is powered directly by the line voltages.

ATS021 can be used in manual or automatic mode. In the first case, the circuit breakers can be

controlled by means of pushbuttons present on the front of the device, while in automatic mode, the

switching logic is controlled directly by the device.

The settings and adjustments can be done by means of dip switches and rotary selectors; the statuses

of the lines, the circuit breakers connected and the device itself are visible by means of special LEDs, if

the unit is powered.

ATS021 can be used in systems with rated frequency 50Hz, 60Hz which can be set by means of dip

switch.

The device can be used in single-phase, three-phase systems with Neutral and three-phase without

neutral, the setting can be done by means of dip switch.

If the ATS021 is used in systems without the Neutral, an external voltage transformer must be used

If the ATS021 is used in single-phase systems the Neutral wire must be connected.

Introduction

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